What Is Sickle Cell Anemia? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Red blood cells that contain normal hemoglobin are disc-shaped and flexible, so they move easily through both large and small blood vessels. People with sickle cell anemia inherit a defective hemoglobin S gene that can cause rigid protein strands to form within red blood cells. This causes the cells to become shaped like a sickle, the farming tool with a semicircular blade like a crescent moon, giving both the cells and the disease their name.

These sickle-shaped cells are not flexible and can stick to vessel walls, causing inflammation in the blood vessels and blockages that can stop or slow the flow of blood.

The body, which is always making new red blood cells to replace the old cells, may have trouble keeping up with how fast the cells are being destroyed. This leads to an overall shortage of red blood cells in the body and, consequently, anemia.

In addition to anemia, the disease can cause other health problems, including infections, stroke, and kidney disease. These health issues can be long-term and can reduce life expectancy.

Pain and fatigue are prominent symptoms of this disorder. The fatigue results from anemia, or a deficiency of healthy red blood cells. The degree of anemia varies among individuals.

• Skin that’s paler than normal
• Yellowish skin, eyes, or mouth (jaundice)
• Difficulty concentrating
• Shortness of breath, especially during exercise
• Dark-colored urine
• Fever
• Weakness
• Dizziness
• Confusion
• Inability to handle physical activity
• Enlarged spleen and liver
• Increased heart rate
• Heart murmur

Common early symptoms include the following:

• Jaundice
• Fatigue
• Fussiness
• Painful swelling of feet and hands (known as dactylitis)
• Frequent infections, especially pneumonia

The severity of symptoms varies from person to person and changes over time. Some people have mild symptoms, while others require frequent hospitalizations to treat more serious symptoms and complications.

• Fever above 101 degrees F
• Difficulty breathing
• Pain in the chest
• Swelling of the abdomen
• Severe headache
• Sudden weakness or loss of feeling and movement
• Seizures
• Painful erection of the penis lasting more than four hours

To have sickle cell anemia, a person must inherit two sickle hemoglobin genes, one from each parent. People with sickle cell trait (meaning they inherited only one sickle hemoglobin gene) generally don’t have symptoms of sickle cell disease, but they can pass the sickle hemoglobin gene on to their children.

Having a family history of sickle cell disease increases your risk for the disease.

Sickle cell anemia is diagnosed through blood testing.

A blood test will demonstrate the following situations:

• Your hemoglobin is normal.
• You have sickle cell anemia or another sickle cell disease.
• You have sickle cell trait (meaning you are a carrier for the disease).

In the United States, all newborns are screened for sickle cell status. Early diagnosis is important to better prevent complications.

Prognosis of Sickle Cell Anemia

Treatment of sickle cell anemia and its symptoms includes these options:

• Daily penicillin for children to prevent related possible infections
• Routine vaccinations to prevent possible infections
• Hydroxyurea, which helps prevent red blood cells from sickling and improves anemia
• Voxelotor (Oxbryta), a drug approved by the Food and Drug Administration (FDA) in 2019 to treat sickle cell disease
• Crizanlizumab (Adakveo), a medicine administered through an IV in a vein and approved in 2019 by the FDA for pain crises
• Glutamine (Endari), a drug FDA-approved to help reduce acute complications of sickle cell disease
• Pain-relieving medications, including narcotics
• Blood transfusions to lower the risk of stroke and other complications
• Lifestyle measures, including drinking plenty of water and avoiding extreme physical exertion

There is no known way to prevent sickle cell anemia. However, you can find out if you carry the gene mutation through a simple blood test. If you don’t have sickle cell anemia but people in your family do, you may have inherited one sickle cell gene; this is referred to as sickle cell trait. If you carry the gene, your chances increase for having a child with either the disease or sickle cell trait.

To be born with sickle cell anemia, a child must inherit two sickle cell gene mutations, one from each parent.

If you carry the mutated gene and your partner carries the mutated gene, there is a 1 in 4 chance that your child will have sickle cell anemia; a 1 in 2 chance they will become a carrier; and a 1 in 4 chance they will not acquire the disease.

If one of you carries the trait, there is a 1 in 2 chance that your child will also carry the trait — but there is no chance they can get the disease.

A few simple steps can help prevent and reduce the number of pain crises:

• Drinking plenty of water
• Avoiding getting too hot or cold
• Avoiding exposure to high altitudes
• Avoiding places or situations where there might be low oxygen levels, such as mountain climbing or extremely intense exercise

People with sickle cell anemia are at a greater risk than those without the condition for problems, including conditions related to the heart, lungs, and kidneys.

• Acute chest syndrome, a medical emergency caused by sickling of the blood vessels of the lungs, which results in damaged lung tissue, chest pain, fever, and difficulty breathing
• Acute pain crisis, which involves sharp, intense, stabbing, or throbbing pain that occurs almost anywhere in the body and is brought on by sickle cells blocking blood flow
• Chronic kidney disease
• Chronic pain
• Organ damage due to sickle cells blocking blood flow, thus depriving organs of blood and oxygen
• Delayed growth and puberty
• Eye problems, such as injury to blood vessels in the eye that could result in vision loss
• Gallstones
• Heart problems, including coronary heart disease and pulmonary hypertension
• Infections due to damage to the spleen
• Joint problems
• Kidney problems
• Leg ulcers
• Liver problems
• Increased risk of miscarriage, premature birth, and low-weight babies
• Priapism, which is a prolonged, painful erection caused by sickle cells blocking blood flow out of the erect penis
• Severe anemia, which can be potentially life-threatening
• Stroke
• Sudden exercise death

Sickle cell disease occurs in 1 of every 365 Black Americans. The disease occurs in 1 of every 16,300 Hispanic Americans.

American Sickle Cell Anemia Association

This organization, founded in 1971, is the oldest sickle cell research, education, and social services organization in the United States. On its website, you can find information for support groups in your area.

American Society of Hematology

The world’s largest professional society concerned with the causes and treatments of blood disorders, including sickle cell anemia, ASH provides news on clinical and research advances on its website.

Be the Match

This organization’s website has the latest information about blood or bone marrow transplants, along with information about joining clinical trials related to the disease.

National Organization for Rare Disorders

A great resource for information about sickle cell disease, this group’s website links to current clinical trials and offers valuable information for patients and caregivers.

Sickle Cell Disease Association of America

On this site you’ll find information about the organization’s peer-to-peer mentoring program, which helps adolescents and young adults as they transition into adult sickle cell health services. It also features a provider network and advocacy and research information.

Sickle Cell Society 

On this site you can read blog posts by people with sickle cell disease, sharing their experiences and challenges that accompany living with the disease.